Window Occlusion Imager Near Focal Plane

ABSTRACT

The present disclosure relates to optical systems and methods of their operation. An example optical system includes an optical component and one or more light sources configured to emit a light signal. The light signal interacts with the optical component so as to provide an interaction light signal. The optical system also includes a detector configured to detect at least a portion of the interaction light signal as a detected light signal. The optical system additionally includes a controller configured to carry out operations including causing the one or more light sources to emit the light signal and receiving the detected light signal from the detector. The operations also include determining, based on the detected light signal, that one or more defects are associated with the optical component.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 16/532,688 filed Aug. 6, 2019, the contents of which are herebyincorporated by reference.

BACKGROUND

Light detection and ranging (LIDAR) devices may estimate distances toobjects in a given environment by emitting light pulses into theenvironment and determining a respective time of flight for each lightpulse. The time of flight of each light pulse can be used to estimatedistances to reflective objects in the environment and/or to create athree-dimensional point cloud indicative of reflective objects in theenvironment. However, optical aberrations and/or defects along theoptical path of the light pulses can lead to erroneous point cloudand/or distance information.

SUMMARY

Example embodiments relate to methods and systems for detectingocclusions (e.g., the presence of debris) on or defects (e.g., cracks,impurities, scratches, voids, air bubbles, etc.) within an opticalcomponent of a LIDAR device or another type of optical system (e.g., acamera).

In a first aspect, an optical system is provided. The optical systemincludes an optical component and one or more light sources configuredto emit a light signal. The light signal interacts with the opticalcomponent so as to provide an interaction light signal. The opticalsystem also includes a detector configured to detect at least a portionof the interaction light signal as a detected light signal. The opticalsystem additionally includes a controller having at least one processorand at least one memory. The at least one processor executesinstructions stored in the at least one memory so as to carry outoperations. The operations include causing the one or more light sourcesto emit the light signal and receiving the detected light signal fromthe detector. The operations additionally include determining, based onthe detected light signal, that one or more defects are associated withthe optical component.

In a second aspect, a method is provided. The method includes causingone or more light sources to emit a light signal. The light signalinteracts with an optical component of an optical system so as toprovide an interaction light signal. The method also includes detecting,by a detector arranged within a housing of the optical system, at leasta portion of the interaction light signal as a detected light signal.The method additionally includes determining, based on the detectedlight signal, that one or more defects are associated with the opticalcomponent.

Other aspects, embodiments, and implementations will become apparent tothose of ordinary skill in the art by reading the following detaileddescription, with reference where appropriate to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates an optical system interacting with an environment,according to an example embodiment.

FIG. 2A illustrates an optical system, according to an exampleembodiment.

FIG. 2B illustrates a portion of the optical system of FIG. 2A,according to an example embodiment.

FIG. 2C illustrates a portion of the optical system of FIG. 2A,according to an example embodiment.

FIG. 2D illustrates a portion of the optical system of FIG. 2A,according to an example embodiment.

FIG. 2E illustrates a portion of the optical system of FIG. 2A,according to an example embodiment.

FIG. 3A illustrates an optical system, according to an exampleembodiment.

FIG. 3B illustrates a portion of the optical system of FIG. 3A,according to an example embodiment.

FIG. 3C illustrates a portion of the optical system of FIG. 3A,according to an example embodiment.

FIG. 4 illustrates images of an optical system, according to exampleembodiments.

FIG. 5A illustrates a vehicle, according to an example embodiment.

FIG. 5B illustrates a vehicle, according to an example embodiment.

FIG. 5C illustrates a vehicle, according to an example embodiment.

FIG. 5D illustrates a vehicle, according to an example embodiment.

FIG. 5E illustrates a vehicle, according to an example embodiment.

FIG. 6 illustrates a method, according to an example embodiment.

DETAILED DESCRIPTION

Example methods, devices, and systems are described herein. It should beunderstood that the words “example” and “exemplary” are used herein tomean “serving as an example, instance, or illustration.” Any embodimentor feature described herein as being an “example” or “exemplary” is notnecessarily to be construed as preferred or advantageous over otherembodiments or features. Other embodiments can be utilized, and otherchanges can be made, without departing from the scope of the subjectmatter presented herein.

Thus, the example embodiments described herein are not meant to belimiting. Aspects of the present disclosure, as generally describedherein, and illustrated in the figures, can be arranged, substituted,combined, separated, and designed in a wide variety of differentconfigurations, all of which are contemplated herein.

Further, unless context suggests otherwise, the features illustrated ineach of the figures may be used in combination with one another. Thus,the figures should be generally viewed as component aspects of one ormore overall embodiments, with the understanding that not allillustrated features are necessary for each embodiment.

I. Overview

Cameras and image sensors are devices used to capture images of a scene.Some cameras (e.g., film cameras) chemically capture an image on film.Other cameras (e.g., digital cameras) electrically capture image data(e.g., using a charge-coupled device (CCD) or complementarymetal-oxide-semiconductor (CMOS) sensors). Images captured by camerascan be analyzed to determine their contents. For example, a processormay execute a machine-learning algorithm in order to identify objects ina scene based on a library of previously classified objects thatincludes objects' shapes, colors, sizes, etc. (e.g., such amachine-learning algorithm can be applied in computer vision in roboticsor other applications).

Cameras can have a variety of features that can distinguish one camerafrom another. For example, cameras and/or images captured by cameras maybe identified by values such as aperture size, f-number, exposure time,shutter speed, depth of field, focal length, International Organizationfor Standardization (ISO) sensitivity (or gain), pixel size, sensorresolution, exposure distance, etc. These features may be based on thelens, the image sensor, and/or additional facets of the camera. Further,these features may also be adjustable within a single camera (e.g., theaperture of a lens on a camera can be adjusted between photographs).

Light detection and ranging (LIDAR) devices may estimate or be used toestimate distances to objects in a given environment. For example, anemitter subsystem of a LIDAR system may emit near-infrared light pulses,which may interact with objects in the LIDAR system's environment. Atleast a portion of the light pulses may be redirected back toward theLIDAR (e.g., due to reflection or scattering) and detected by a receiversubsystem. Conventional receiver subsystems may include a plurality ofdetectors and a corresponding controller configured to determine anarrival time of the respective light pulses with high temporalresolution (e.g., ˜400 ps). The distance between the LIDAR system and agiven object may be determined based on a time of flight of thecorresponding light pulses that interact with the given object. Further,data from LIDAR devices may be used to generate a point cloud (e.g., athree-dimensional point cloud) based on pulses detected by a lightdetector.

In some cases, imperfections of optical components within a camera or aLIDAR device may cause aberrations within the corresponding capturedimages or generated point clouds. For example, a scratch, a crack, asmudge, a deformation, debris, a void, an air bubble, an impurity, adegradation, a discoloration, imperfect transparency, a warp, orcondensation, etc. may cause light from a scene to be directed tounintended/improper regions of an image sensor/light detector, mayprevent light from a scene from ever reaching an image sensor/lightdetector, or may otherwise modify light from a scene (e.g., modifypolarization or wavelength) prior to the light reaching an imagesensor/light detector. Such aberrations can result in improper objectidentification, distance determination, or other errors. Such errorscan, in turn, affect the operation of an autonomous vehicle thatreceives data from the camera or LIDAR device.

Example embodiments relate to methods and systems for detectingocclusions (e.g., the presence of debris) on or defects (e.g., cracks,impurities, scratches, voids, air bubbles, etc.) within an opticalcomponent of a LIDAR device or a camera. For example, example methodsand systems could relate to detecting contamination (e.g., dirt, water,ice, etc.) on an external window of a LIDAR device.

The detection techniques disclosed herein may include emitting a lightsignal from a light source to illuminate the optical component on whicha diagnostic test is being performed. In some embodiments, the lightsource could illuminate one or more surfaces of the optical component.As an example, the illuminated surfaces of the optical component couldbe imaged by one or more cameras located at or near the focal plane ofthe optical system. In some embodiments, the camera could beincorporated into a main image sensor of the optical system. In otherembodiments, the camera could be mounted elsewhere within a housing ofthe optical system so as to image the optical component to inspect itfor occluding features (e.g., dirt, water, ice, etc.) or other types ofaberration-causing elements (e.g., cracks, scratches, etc.). Based onimages captured by the camera, defects or occlusions could beidentified.

In such scenarios, the camera could include a localized or distributedgroup of pixels located on the main image sensor of the LIDAR or camerasystem. Furthermore, the pixels on the main image sensors utilized foraberration detection could be optically coupled to lenses and/or otheroptical elements so that an image of the optical component can bereconstructed upon image capture. For example, the lenses could includeone or more microlenses that are coupled to the aberration-sensingportions of the main image sensor.

In other embodiments, the light emitted from the light source may becoupled into the optical component at one end of the optical component(e.g., along an edge of an optical window). Thereafter, the light maypropagate throughout the body of the optical component via totalinternal reflection (TIR). If no occlusions are present on or defectsare present within the optical component, the light signal may propagateto an opposite end of the optical component (e.g., where it is absorbedby an absorptive baffle, coupled out of the optical component into freespace, or detected by a light detector). If, however, occlusions arepresent on or defects are present within the optical component, thelight signal may be redirected (e.g., to a light detector of the camerasystem/LIDAR device or to a separate light detector used to detectocclusions/defects) and/or absorbed, at least in part. Based on thedetection of light signal (e.g., based on the intensity of the lightsignal and/or the presence of the light signal), the presence of adefect/occlusion may be identified (e.g., by a computing deviceexecuting instructions stored on a non-transitory, computer-readablemedium).

In some embodiments, the type of defect/debris present within/on theoptical component (e.g., a crack in the optical component vs. mud on theoptical component) may also be determined based on the intensity and/orpresence of the light signal. For example, the light source may includeone or more light-emitting diodes (LEDs) or lasers. The LEDs or lasersmay be positioned (e.g., in an array) adjacent to the optical componentand/or embedded within the optical component, in various embodiments.Further, optical qualities (e.g., wavelength and/or polarization) of thelight signal emitted by the light source may be predetermined tocorrespond with various types of debris that could potentially occludethe optical component (e.g., mud, leaves, insects, rain, snow, etc.).For example, a wavelength that is known to reflect from a leaf orgenerate fluorescence in an organic fluorescent compound may be producedby the light source. Additionally or alternatively, optical qualities(e.g., wavelength and/or polarization) of the light signal emitted bythe light source may be predetermined to correspond with various typesof defects that could potentially by present within the opticalcomponent (e.g., cracks, deformations, air bubbles, etc.).

In order to achieve total internal reflection, the light signal may becoupled into the optical component at such an angle so as to achievetotal internal reflection based on the indices of refraction of theoptical component and the surrounding medium (e.g., the light signal maybe coupled into the optical component at a relative high angle ofincidence). In some embodiments, the optical component may be anexternal or internal lens of the camera system or the LIDAR system.Alternatively, the optical component may be an external optical window(e.g., dome) placed between the optics of the camera/LIDAR system andthe external environment. In embodiments where an external opticalwindow is used, the external optical window may be designed so as toenhance the total internal reflection of the light signal. For example,the external optical window may be relatively thin so that thereflection angles of the light signal are relatively shallow withrespect to the curvature of the external optical window (e.g., therebyensuring the total internal reflection condition is satisfied). Such anexternal optical window may be shaped hemispherically or may be shapedas a half-cylinder, in various embodiments.

The diagnostic test may be performed at repeated intervals to ensure theproper functionality of LIDAR devices/cameras. For example, a diagnostictest may be performed every day, hour, minute, thirty seconds, fiveseconds, second, 500 ms, 100 ms, 50 ms, 10 ms, 5 ms, 1 ms, etc. todetermine whether a defect is present on or in the corresponding opticalcomponent. Upon detecting a defect associated with the correspondingoptical component, corrective action may be taken. For example, theoptical component could be cleaned (e.g., using a windshield wiper),repaired (e.g., by a maintenance technician), replaced (e.g., with a newoptical component), realigned, etc. In addition, the corrective actiontaken may correspond to the type of defect detected. For example, if anocclusion on the optical component is detected, a windshield wiper maybe engaged, whereas if a crack in the optical component is detected, areplacement optical component may be ordered and/or installed.

Still further, in some embodiments, an escalation protocol could also beemployed. For example, if a defect is detected, a cleaning routine ofthe optical component may be employed. After the cleaning routine isemployed, another diagnostic test may be performed. If the same defectis still present on/in the optical component, arealignment/recalibration routine may be employed. If, after performingan additional diagnostic test, the defect is still present on/in theoptical component, a replacement optical component may be installed. If,after performing yet another diagnostic test, the defect is stillpresent on/in the optical component, the LIDAR system/the camera may bedecommissioned. If, during any of the intermediate diagnostic tests, itis instead detected that the defect has been corrected, the escalationprotocol may be reset and additional detection events may not beperformed.

II. Example Optical Systems

FIG. 1 illustrates an optical system 100, according to an exampleembodiment. The optical system 100 includes an optical component 110 andone or more light sources 120. In various embodiments, the opticalcomponent 110 could include a lens. In such scenarios, the opticalcomponent 110 could include one or more plano-convex lenses, a prismlens, a cylindrical lens, a conical lens, and/or other type of lens.However, other types of optical components, such as filters, films,mirrors, windows, diffusers, gratings, and/or prisms are contemplatedand possible.

In example embodiments, the one or more light sources 120 could includea light-emitting diode (LED), a laser, an array of LEDs, or an array oflasers. It will be understood that other light-emitting devices arecontemplated and possible within the context of the present disclosure.In such scenarios, the light sources 120 could be configured to emit alight signal 122. The light signal 122 interacts with the opticalcomponent 110 so as to provide an interaction light signal 124.

The optical system 100 also includes a detector 130. The detector 130could be a light-sensitive device that is configured to detect at leasta portion of the interaction light signal 124 as a detected light signal126. In some scenarios, the detector 130 could include at least one of:a charge-coupled device (CCD), a portion of a CCD, an image sensor of acamera, or a portion of an image sensor of a camera. Additionally oralternatively, the detector 130 could include a silicon photomultiplier(SiPM), an avalanche photodiode (APD), a single photon avalanchedetector (SPAD), a cryogenic detector, a photodiode, or aphototransistor. Other photo-sensitive devices or systems are possibleand contemplated herein.

In some embodiments, the optical system 100 may include an image sensor140. For example, the image sensor 140 could include a plurality ofcharge-coupled device (CCD) elements and/or a plurality of complementarymetal-oxide-semiconductor (CMOS) elements. In some embodiments, theoptical system 100 could include a plurality of image sensors. In anexample embodiment, the image sensor 140 could be configured to detectlight in the infrared spectrum (e.g., about 700 nanometers to about 1000nanometers) and/or within the visible spectrum (e.g., about 400nanometers to about 700 nanometers). Using the image sensor 140 to senselight in other spectral ranges (e.g., long-wavelength infrared (LWIR)light having wavelengths between 8-12 microns) is possible andcontemplated herein.

The image sensor 140 could be configured (e.g., sized or dimensioned)according to an image sensor format. For example, the image sensor 140could include a full-frame (e.g., 35 millimeter) format sensor.Additionally or alternatively, the image sensor 140 could include “cropsensor” formats, such as APS-C (e.g., 28.4 mm diagonal) or one inch(e.g., 15.86 mm diagonal) formats. Other image sensor formats arecontemplated and possible within the scope of the present disclosure.

The optical system 100 additionally includes a controller 150. In someembodiments, the controller 150 could be a read-out integrated circuit(ROIC) that is electrically-coupled to the image sensor 140. Thecontroller 150 includes at least one of a field-programmable gate array(FPGA) or an application-specific integrated circuit (ASIC).Additionally or alternatively, the controller 150 may include one ormore processors 152 and a memory 154. The one or more processors 152 mayinclude a general-purpose processor or a special-purpose processor(e.g., digital signal processors, etc.). The one or more processors 152may be configured to execute computer-readable program instructions thatare stored in the memory 154. In some embodiments, the one or moreprocessors 152 may execute the program instructions to provide at leastsome of the functionality and operations described herein.

The memory 154 may include or take the form of one or morecomputer-readable storage media that may be read or accessed by the oneor more processors 152. The one or more computer-readable storage mediacan include volatile and/or non-volatile storage components, such asoptical, magnetic, organic or other memory or disc storage, which may beintegrated in whole or in part with at least one of the one or moreprocessors 152. In some embodiments, the memory 154 may be implementedusing a single physical device (e.g., one optical, magnetic, organic orother memory or disc storage unit), while in other embodiments, thememory 154 can be implemented using two or more physical devices.

As noted, the memory 154 may include computer-readable programinstructions that relate to operations of optical system 100. The atleast one processor 152 executes instructions stored in the at least onememory 154 so as to carry out operations.

The operations include causing the one or more light sources 120 to emitthe light signal 122. In some embodiments, the light signal 122 could beemitted through the optical component 110 and towards an environment 10of the optical system 100.

The operations also include receiving the detected light signal 126 fromthe detector 130.

The operations also include determining, based on the detected lightsignal 126, that one or more defects 118 are associated with the opticalcomponent 110 (e.g., present in a body 116 of the optical component 110or on a surface of the optical component 110, including the firstoptical component surface 112 and/or second optical component surface114).

FIG. 2A illustrates an optical system 200, according to an exampleembodiment. Optical system 200 could be similar or identical to opticalsystem 100. Some embodiments could include a small camera and an LEDilluminator placed at or adjacent to the focal plane of an image sensor.In such scenarios, the image plane may be sparse enough to provide roomfor the occlusion detection camera without causing a substantiveocclusion in the image.

For example, in some embodiments, the optical system 200 could includean optical axis 206. The optical system 200 could also include a focaldistance 204 along the optical axis 206 defining a focal plane 202. Invarious embodiments, the optical system 200 could include a plurality ofoptical elements (e.g., lenses) 110 b-110 g. For example, the opticalelements 110 b-110 g could include lenses of an optical lens assembly.

In some embodiments, the image sensor 140 could be arranged along thefocal plane 202. In such scenarios, the detector 130 could also bearranged along the focal plane 202.

As illustrated in FIG. 2A, in some embodiments, the detector 130 couldbe arranged to detect the detected light signal 126 along a lightdetection axis, wherein the light detection axis is arranged at anon-zero offset angle 210 (e.g., at least 5 degrees off-axis) withrespect to the optical axis 206.

FIG. 2B illustrates a portion 220 of the optical system 200 of FIG. 2A,according to an example embodiment. In some embodiments, the imagesensor 140 could include a plurality of photodetector elements 222(e.g., 256 pixels, 1000 pixels, up to 20 megapixels or more). In suchscenarios, the detector 130 could include at least a portion of thephotodetector elements 222. For example, the detector 130 could include100×100 pixels of a megapixel-scale image sensor array. It will beunderstood that the detector 130 could include more or fewerphotodetector elements of the overall image sensor 140.

FIG. 2C illustrates a portion 230 of the optical system 200 of FIG. 2A,according to an example embodiment. As illustrated in FIG. 2C, the imagesensor 140 could include a plurality of detectors (e.g., detector 130 aand detector 130 b). For example, the plurality of detectors couldcorrespond to a plurality of pixels of the image sensor 140.

FIG. 2D illustrates a portion 240 of the optical system 200 of FIG. 2A,according to an example embodiment. As indicated in FIG. 2D, thedetector 130 could include a first optical filter 242 on a first regionof the detector and a second optical filter 244 on a second region ofthe detector 130. In such scenarios, the first optical filter 242 andthe second optical filter 244 could be configured to select differentranges of wavelengths (e.g., spectral pass bands).

In some embodiments, the detector 130 could include one or moremicrolenses 246. The microlens(es) 246 could be optically coupled to thedetector 130, the first optical filter 242, and/or the second opticalfilter 244.

In some embodiments, the wavelength range corresponding to the firstoptical filter 242 could include a wavelength of the light signal 122.Additionally or alternatively, the wavelength range corresponding to thesecond optical filter 244 could be configured to exclude the wavelengthof the light signal 122. In such scenarios, the operations carried outby the controller 150 could also include comparing a first image portionprovided by the first region of the detector 130 to a second imageportion provided by the second region of the detector 130. Based on thecomparison, a defect type of at least one of the one or more defects(e.g., scratch, bug, dirt, water, snow, crack, etc.) could bedetermined.

FIG. 2E illustrates a portion 250 of the optical system 200 of FIG. 2A,according to an example embodiment. In some embodiments, a wavelength ofthe light signal 122 could correspond to an excitation wavelength for anorganic fluorescent compound (e.g., a fluorophore). In such scenarios,the detector 130 could include an optical filter (e.g., first opticalfilter 242) that passes an emission wavelength of the organicfluorescent compound and blocks the excitation wavelength of the organicfluorescent compound. In such scenarios, at least a portion of thedetected light signal 126 could include the emission wavelength. In someembodiments, the operations could also include determining, based on thedetected light signal 126, that one or more organic fluorescentcompounds (e.g., defect 118) are present on the surface of the opticalcomponent 110 a. Such features could provide information on whether thedefect 118 could be an insect with the particular organic fluorescentcompound (e.g., firefly “splatter”).

FIG. 3A illustrates an optical system 300, according to an exampleembodiment. Optical system 300 could be similar or identical in variousaspects to that of optical system 100 and/or optical system 200, asillustrated and described in reference to FIGS. 1 and 2A-2E. In someembodiments, the light signal 122 could be directed into a body 116 ofthe optical component 110 a so as to be reflected within the body 116 ofthe optical component 110 a via total internal reflection 302. In someembodiments, the light signal 122 could be directed into the body 116 ata desired angle so as to achieve total internal reflection 302.

In example embodiments, the one or more light sources 120 could bepositioned adjacent to a first end 304 of the optical component 110 a.In such scenarios, the light signal 122 may optically couple into theoptical component 110 a via the first end 304.

FIG. 3B illustrates a portion 320 of the optical system 300 of FIG. 3A,according to an example embodiment. In such a scenario, the detector 130could be positioned at a second end 322 of the optical component 110 athat is opposite the first end 304 of the optical component 110 a.

Additionally or alternatively, the optical component 110 a could beovermolded over the one or more light sources 120 such that the one ormore light sources 120 are at least partially embedded within theoptical component 110 a. Thus, the one or more light sources 120 couldbe embedded within or otherwise optically and physically coupled to theoptical component 110 a.

FIG. 3C illustrates a portion 330 of the optical system 300 of FIG. 3A,according to an example embodiment. In some examples, the opticalcomponent 110 a could be an external optical window (e.g., a transparenthousing). In such scenarios, the external optical window could be curved(e.g., hemispherically shaped or half-cylindrically shaped). It will beunderstood that the external optical window could have other shapes orforms.

FIG. 4 illustrates various images 400 of an optical component, accordingto example embodiments. The images 400 could include output from animage sensor (e.g., image sensor 140) and/or a detector (e.g., detector130). As an example, the images 400 may include images from an innersurface of an optical component 110 a. However, other optical componentscould be imaged, as described elsewhere herein.

In various embodiments, the images 400 could illustrate no window 402, awhite diffuser 404, water droplets 406, a ruler 408, a clean window 410,a dirty window 412, and other foreign objects 414. In some embodiments,the various images 400 could undergo image analysis by controller 150and/or another computing device. In such scenarios, the controller 150and/or another computing device could, based on the image analysis,determine a type of occlusion (e.g., water droplets, clean/dirty window,etc.).

In some embodiments, one or more sensor units incorporating opticalsystem 100, optical system 200, and/or optical system 300 could beattached or otherwise mounted to a vehicle, as described below.

III. Example Vehicles

FIGS. 5A, 5B, 5C, 5D, and 5E illustrate a vehicle 500, according to anexample embodiment. The vehicle 500 could be a semi- or fully-autonomousvehicle. While FIG. 5 illustrates vehicle 500 as being an automobile(e.g., a passenger van), it will be understood that vehicle 500 couldinclude another type of autonomous vehicle, robot, or drone that cannavigate within its environment using sensors and other informationabout its environment.

The vehicle 500 may include one or more sensor systems 502, 504, 506,508, and 510. In some embodiments, sensor systems 502, 504, 506, 508,and 510 could include optical systems 100, 200, and/or 300 asillustrated and described in relation to FIGS. 1, 2A-2E, and 3A-3C. Inother words, the optical systems described elsewhere herein could becoupled to the vehicle 500 and/or could be utilized in conjunction withvarious operations of the vehicle 500. As an example, optical systems100, 200, and/or 300 could be implemented in, or in conjunction with,the sensor systems 502, 504, 506, 508, and 510, which could be utilizedin self-driving or other types of navigation, planning, and/or mappingoperations of the vehicle 500.

While the one or more sensor systems 502, 504, 506, 508, and 510 areillustrated on certain locations on vehicle 500, it will be understoodthat more or fewer sensor systems could be utilized with vehicle 500.Furthermore, the locations of such sensor systems could be adjusted,modified, or otherwise changed as compared to the locations of thesensor systems illustrated in FIGS. 5A, 5B, 5C, 5D, and 5E.

In some embodiments, the one or more sensor systems 502, 504, 506, 508,and 510 could additionally or alternatively include LIDAR sensors. Forexample, the LIDAR sensors could include a plurality of light-emitterdevices arranged over a range of angles with respect to a given plane(e.g., the x-y plane). For example, one or more of the sensor systems502, 504, 506, 508, and 510 may be configured to rotate about an axis(e.g., the z-axis) perpendicular to the given plane so as to illuminatean environment around the vehicle 500 with light pulses. Based ondetecting various aspects of reflected light pulses (e.g., the elapsedtime of flight, polarization, intensity, etc.), information about theenvironment may be determined.

In an example embodiment, sensor systems 502, 504, 506, 508, and 510 maybe configured to provide respective point cloud information that mayrelate to physical objects within the environment of the vehicle 500.While vehicle 500 and sensor systems 502, 504, 506, 508, and 510 areillustrated as including certain features, it will be understood thatother types of sensor systems are contemplated within the scope of thepresent disclosure.

An example embodiment may include a system having a plurality oflight-emitter devices. The system may include a transmit block of aLIDAR device. For example, the system may be, or may be part of, a LIDARdevice of a vehicle (e.g., a car, a truck, a motorcycle, a golf cart, anaerial vehicle, a boat, etc.). Each light-emitter device of theplurality of light-emitter devices is configured to emit light pulsesalong a respective beam elevation angle. The respective beam elevationangles could be based on a reference angle or reference plane, asdescribed elsewhere herein. In some embodiments, the reference plane maybe based on an axis of motion of the vehicle 500.

While LIDAR systems with single light-emitter devices are described andillustrated herein, LIDAR systems with multiple light-emitter devices(e.g., a light-emitter device with multiple laser bars on a single laserdie) are also contemplated. For example, light pulses emitted by one ormore laser diodes may be controllably directed about an environment ofthe system. The angle of emission of the light pulses may be adjusted bya scanning device such as, for instance, a mechanical scanning mirrorand/or a rotational motor. For example, the scanning devices couldrotate in a reciprocating motion about a given axis and/or rotate abouta vertical axis. In another embodiment, the light-emitter device mayemit light pulses towards a spinning prism mirror, which may cause thelight pulses to be emitted into the environment based on an angle of theprism mirror angle when interacting with each light pulse. Additionallyor alternatively, scanning optics and/or other types ofelectro-opto-mechanical devices are possible to scan the light pulsesabout the environment.

In some embodiments, a single light-emitter device may emit light pulsesaccording to a variable shot schedule and/or with variable power pershot, as described herein. That is, emission power and/or timing of eachlaser pulse or shot may be based on a respective elevation angle of theshot. Furthermore, the variable shot schedule could be based onproviding a desired vertical spacing at a given distance from the LIDARsystem or from a surface (e.g., a front bumper) of a given vehiclesupporting the LIDAR system. As an example, when the light pulses fromthe light-emitter device are directed downwards, the power-per-shotcould be decreased due to a shorter anticipated maximum distance totarget. Conversely, light pulses emitted by the light-emitter device atan elevation angle above a reference plane may have a relatively higherpower-per-shot so as to provide sufficient signal-to-noise to adequatelydetect pulses that travel longer distances.

In some embodiments, the power/energy-per-shot could be controlled foreach shot in a dynamic fashion. In other embodiments, thepower/energy-per-shot could be controlled for successive set of severalpulses (e.g., 10 light pulses). That is, the characteristics of thelight pulse train could be changed on a per-pulse basis and/or aper-several-pulse basis.

While FIGS. 5A-5E illustrate various LIDAR sensors attached to thevehicle 500, it will be understood that the vehicle 500 couldincorporate other types of sensors, such as cameras, ultrasonic sensors,and/or radar sensors.

IV. Example Methods

FIG. 6 illustrates a method 600, according to an example embodiment. Itwill be understood that the method 600 may include fewer or more stepsor blocks than those expressly illustrated or otherwise disclosedherein. Furthermore, respective steps or blocks of method 600 may beperformed in any order and each step or block may be performed one ormore times. In some embodiments, some or all of the blocks or steps ofmethod 600 may relate to elements of the optical systems 100, 200, 300and/or the vehicle 500 as illustrated and described in relation to FIGS.1, 2A-2E, 3A-3C, and 5A-5E.

Block 602 includes causing one or more light sources (e.g., light source120) to emit a light signal (e.g., light signal 122). Causing the lightsource to emit the light signal could include causing a pulser circuitto transmit a current or voltage pulse to the light source so as togenerate one or more light pulses. In some embodiments, the light signal122 interacts with an optical component (e.g., optical component 110) ofan optical system (e.g., optical system 100) so as to provide aninteraction light signal (e.g., interaction light signal 124).

Block 604 includes detecting, at a detector (e.g., detector 130)arranged within a housing of the optical system, at least a portion ofthe interaction light signal as a detected light signal (e.g., detectedlight signal 126). In example embodiments, receiving the detected lightsignal could include receiving information indicative of one or moredefects on the optical component. In such scenarios, the informationcould include an image of the optical component and/or information aboutphoton intensity from an environment of the optical system.

Block 606 includes determining, based on the detected light signal, thatat least one defect (e.g., defect 118) is associated with the opticalcomponent. As an example, the defect could be present in a body (e.g.,body 116) of the optical component or on a surface of the opticalcomponent (e.g., first optical component surface 112 or second opticalcomponent surface 114). In some embodiments, determining at least onedefect could include performing an image analysis (e.g., objectrecognition) on information received from the detector or the imagesensor. As an example, the detector or image sensor could provide imagessuch as those illustrated and described with reference to FIG. 4.

In some embodiments, the method 600 could additionally include takingcorrective action if it is determined that one or more defects arepresent in the body of the optical component or on the surface of theoptical component.

In various embodiments, taking corrective action could include cleaning,repairing, recalibrating, replacing, realigning, or decommissioning atleast one of the detector or the optical component.

In example embodiments, causing the one or more light sources to emitthe light signal could include causing the one or more light sources toemit the light signal toward the body of the optical component at suchan angle so as to be reflected within the body of the optical componentvia total internal reflection.

Additionally or alternatively, method 600 could include determining adefect type of at least one defect, wherein the defect type comprises atleast one of: a scratch, a crack, a smudge, a deformation, debris, anair bubble, an impurity, a degradation, a discoloration, imperfecttransparency, a warp, or condensation (e.g., a water droplet).

The particular arrangements shown in the Figures should not be viewed aslimiting. It should be understood that other embodiments may includemore or less of each element shown in a given Figure. Further, some ofthe illustrated elements may be combined or omitted. Yet further, anillustrative embodiment may include elements that are not illustrated inthe Figures.

A step or block that represents a processing of information cancorrespond to circuitry that can be configured to perform the specificlogical functions of a herein-described method or technique.Alternatively or additionally, a step or block that represents aprocessing of information can correspond to a module, a segment, or aportion of program code (including related data). The program code caninclude one or more instructions executable by a processor forimplementing specific logical functions or actions in the method ortechnique. The program code and/or related data can be stored on anytype of computer readable medium such as a storage device including adisk, hard drive, or other storage medium.

The computer readable medium can also include non-transitory computerreadable media such as computer-readable media that store data for shortperiods of time like register memory, processor cache, and random accessmemory (RAM). The computer readable media can also includenon-transitory computer readable media that store program code and/ordata for longer periods of time. Thus, the computer readable media mayinclude secondary or persistent long term storage, like read only memory(ROM), optical or magnetic disks, compact-disc read only memory(CD-ROM), for example. The computer readable media can also be any othervolatile or non-volatile storage systems. A computer readable medium canbe considered a computer readable storage medium, for example, or atangible storage device.

While various examples and embodiments have been disclosed, otherexamples and embodiments will be apparent to those skilled in the art.The various disclosed examples and embodiments are for purposes ofillustration and are not intended to be limiting, with the true scopebeing indicated by the following claims.

What is claimed is:
 1. An optical system comprising: an external opticalwindow; one or more light sources configured to emit a light signal,wherein the light signal interacts with the external optical window soas to provide an interaction light signal; and a defect detectorconfigured to detect at least a portion of the interaction light signalas a detected light signal; and a controller comprising at least oneprocessor and at least one memory, wherein the at least one processorexecutes instructions stored in the at least one memory so as to carryout operations, the operations comprising: causing the one or more lightsources to emit the light signal; and determining, based on a detectedlight signal from the defect detector, that one or more defects areassociated with the external optical window, wherein the light signal isdirected into the external optical window at such an angle so as to bereflected within the external optical window via total internalreflection, and wherein the external optical window is designed toenhance the total internal reflection of the light signal.
 2. Theoptical system of claim 1, wherein the optical system further comprises:an optical axis; a focal distance along the optical axis defining afocal plane; and a main image sensor arranged along the focal plane,wherein the defect detector is arranged along the focal plane.
 3. Theoptical system of claim 2, wherein the main image sensor comprises aplurality of photodetector elements, wherein the defect detectorcomprises at least a portion of the photodetector elements.
 4. Theoptical system of claim 2, wherein the defect detector is arranged todetect the detected light signal along a light detection axis, whereinthe light detection axis is at least 5 degrees off-axis with respect tothe optical axis.
 5. The optical system of claim 1, wherein the one ormore light sources comprise a light-emitting diode (LED), a laser, anarray of LEDs, or an array of lasers.
 6. The optical system of claim 1,wherein the one or more light sources are positioned adjacent to a firstend of the external optical window, and wherein the light signal couplesinto the external optical window via the first end.
 7. The opticalsystem of claim 6, wherein the defect detector is positioned at a secondend of the external optical window, wherein the second end is oppositethe first end.
 8. The optical system of claim 1, wherein the externaloptical window is overmolded over the one or more light sources suchthat the one or more light sources are at least partially embeddedwithin the external optical window.
 9. The optical system of claim 1,wherein the one or more light sources are at least partially embeddedwithin the external optical window.
 10. The optical system of claim 1,wherein the external optical window has a hemispherical shape or ahalf-cylinder shape.
 11. The optical system of claim 1, wherein thedefect detector comprises at least one of: a charge-coupled device(CCD), a portion of a CCD, an image sensor of a camera, or a portion ofan image sensor of a camera.
 12. The optical system of claim 1, whereinthe defect detector comprises a silicon photomultiplier (SiPM), anavalanche photodiode (APD), a single photon avalanche detector (SPAD), acryogenic detector, a photodiode, or a phototransistor.
 13. The opticalsystem of claim 1, further comprising a first optical filter that isoptically coupled to a first region of the defect detector and a secondoptical filter that is optically coupled a second region of the defectdetector, wherein the first optical filter and the second optical filterselect different ranges of wavelengths, wherein the wavelength rangeselected by the first optical filter includes a wavelength of the lightsignal, wherein the wavelength range selected by the second opticalfilter excludes the wavelength of the light signal, and wherein theoperations further comprise: comparing a first image portion provided bythe first region of the defect detector to a second image portionprovided by the second region of the defect detector; and determining adefect type of at least one of the one or more defects based on thecomparison.
 14. The optical system of claim 1, wherein a wavelength ofthe light signal corresponds to an excitation wavelength for an organicfluorescent compound, wherein the defect detector comprises an opticalfilter that passes an emission wavelength of the organic fluorescentcompound and blocks the excitation wavelength of the organic fluorescentcompound, wherein at least a portion of the detected light signalcomprises the emission wavelength, and wherein the operations furthercomprise: determining, based on the detected light signal, that one ormore organic fluorescent compounds are present on a surface of theexternal optical window.
 15. A method comprising: causing one or morelight sources to emit a light signal, wherein the light signal interactswith an external optical window of an optical system so as to provide aninteraction light signal, wherein the light signal is directed into theexternal optical window at such an angle so as to be reflected withinthe external optical window via total internal reflection, and whereinthe external optical window is designed to enhance the total internalreflection of the light signal; detecting, by a defect detector arrangedwithin a housing of the optical system, at least a portion of theinteraction light signal as a detected light signal; and determining,based on the detected light signal, that one or more defects areassociated with the external optical window.
 16. The method of claim 15,further comprising: taking corrective action in response to adetermination that one or more defects are associated with the externaloptical window.
 17. The method of claim 16, wherein taking correctiveaction comprises: cleaning, repairing, recalibrating, replacing,realigning, or decommissioning the external optical window.
 18. Themethod of claim 15, wherein causing the one or more light sources toemit the light signal comprises causing the one or more light sources toemit the light signal toward the external optical window at such anangle so as to be reflected within the external optical window via totalinternal reflection.
 19. The method of claim 15, further comprisingdetermining a defect type of at least one of the one or more defects,wherein the defect type comprises at least one of: a scratch, a crack, asmudge, a deformation, debris, an air bubble, an impurity, adegradation, a discoloration, imperfect transparency, a warp, orcondensation.
 20. A vehicle comprising: at least one optical system, theoptical system comprising: an external optical window; one or more lightsources configured to emit a light signal, wherein the light signalinteracts with the external optical window so as to provide aninteraction light signal; and a defect detector configured to detect atleast a portion of the interaction light signal as a detected lightsignal; and a controller comprising at least one processor and at leastone memory, wherein the at least one processor executes instructionsstored in the at least one memory so as to carry out operations, theoperations comprising: causing the one or more light sources to emit thelight signal; receiving the detected light signal from the defectdetector; and determining, based on the detected light signal, that oneor more defects are associated with the external optical window, whereinthe light signal is directed into the external optical window at such anangle so as to be reflected within the external optical window via totalinternal reflection, and wherein the external optical window is designedto enhance the total internal reflection of the light signal.